Data Migration Monitoring Metrics

If your DM cluster is deployed using DM-Ansible, the monitoring system is also deployed at the same time. This document describes the monitoring metrics provided by DM-worker.

Note

Currently, DM-master does not provide monitoring metrics yet.

Task

In the Grafana dashboard, the default name of DM is DM-task.

`overview`

overview contains some monitoring metrics of all the DM-worker instances in the currently selected task. The current default alert rule is only for a single DM-worker instance.

Metric name	Description	Alert	Severity level
task state	The state of subtasks for migration	N/A	N/A
storage capacity	The total storage capacity of the disk occupied by relay logs	N/A	N/A
storage remain	The remaining storage capacity of the disk occupied by relay logs	N/A	N/A
binlog file gap between master and relay	The number of binlog files by which the `relay` processing unit is behind the upstream master	N/A	N/A
load progress	The percentage of the completed loading process of the load unit. The value is between 0%~100%	N/A	N/A
binlog file gap between master and syncer	The number of binlog files by which the binlog replication unit is behind the upstream master	N/A	N/A
shard lock resolving	Whether the current subtask is waiting for sharding DDL migration. A value greater than 0 means that the current subtask is waiting for sharding DDL migration	N/A	N/A

Task state

Metric name	Description	Alert	Severity level
task state	The state of subtasks	An alert occurs when the subtask has been paused for more than 20 minutes	critical

Relay log

Metric name	Description	Alert	Severity level
storage capacity	The storage capacity of the disk occupied by the relay log	N/A	N/A
storage remain	The remaining storage capacity of the disk occupied by the relay log	An alert is needed once the value is smaller than 10G	critical
process exits with error	The relay log encounters an error within the DM-worker and exits	Immediate alerts	critical
relay log data corruption	The number of corrupted relay log files	Immediate alerts	emergency
fail to read binlog from master	The number of errors encountered when the relay log reads the binlog from the upstream MySQL	Immediate alerts	critical
fail to write relay log	The number of errors encountered when the relay log writes the binlog to disks	Immediate alerts	critical
binlog file index	The largest index number of relay log files. For example, "value = 1" indicates "relay-log.000001"	N/A	N/A
binlog file gap between master and relay	The number of binlog files in the relay log that are behind the upstream master	An alert occurs when the number of binlog files by which the `relay` processing unit is behind the upstream master exceeds one (>1) and the condition lasts over 10 minutes	critical
binlog pos	The write offset of the latest relay log file	N/A	N/A
read binlog event duration	The duration that the relay log reads binlog from the upstream MySQL (in seconds)	N/A	N/A
write relay log duration	The duration that the relay log writes binlog into the disks each time (in seconds)	N/A	N/A
binlog event size	The size of a single binlog event that the relay log writes into the disks	N/A	N/A

Dump/Load unit

The following metrics show only when task-mode is in the full or all mode.

Metric name	Description	Alert	Severity level
load progress	The percentage of the completed loading process of the load unit. The value range is 0%~100%	N/A	N/A
data file size	The total size of the data files (includes the `INSERT INTO` statement) in the full data imported by the load unit	N/A	N/A
dump process exits with error	The dump unit encounters an error within the DM-worker and exits	Immediate alerts	critical
load process exits with error	The load unit encounters an error within the DM-worker and exits	Immediate alerts	critical
table count	The total number of tables in the full data imported by the load unit	N/A	N/A
data file count	The total number of data files (includes the `INSERT INTO` statement) in the full data imported by the load unit	N/A	N/A
transaction execution latency	The latency of executing a transaction by the load unit (in seconds)	N/A	N/A
statement execution latency	The duration of executing a statement by the load unit (in seconds)	N/A	N/A

Binlog replication

The following metrics show only when task-mode is in the incremental or all mode.

Metric name	Description	Alert	Severity level
remaining time to sync	The predicted remaining time it takes `syncer` to be completely migrated with the master (in minutes)	N/A	N/A
replicate lag	The latency time it takes to replicate the binlog from master to `syncer` (in seconds)	N/A	N/A
process exist with error	The binlog replication unit encounters an error within the DM-worker and exits	Immediate alerts	critical
binlog file gap between master and syncer	The number of binlog files by which the `syncer` processing unit is behind the master	An alert occurs when the number of binlog files by which the `syncer` processing unit is behind the master exceeds one (>1) and the condition lasts over 10 minutes	critical
binlog file gap between relay and syncer	The number of binlog files by which `syncer` is behind `relay`	An alert occurs when the number of binlog files by which the `syncer` processing unit is behind the `relay` processing unit exceeds one (>1) and the condition lasts over 10 minutes	critical
binlog event QPS	The number of binlog events received per unit of time (this number does not include the events that need to be skipped)	N/A	N/A
skipped binlog event QPS	The number of binlog events received per unit of time that need to be skipped	N/A	N/A
read binlog event duration	The duration that the binlog replication unit reads the binlog from the relay log or the upstream MySQL (in seconds)	N/A	N/A
transform binlog event duration	The duration that the binlog replication unit parses and transforms the binlog into SQL statements (in seconds)	N/A	N/A
dispatch binlog event duration	The duration that the binlog replication unit dispatches a binlog event (in seconds)	N/A	N/A
transaction execution latency	The duration that the binlog replication unit executes the transaction to the downstream (in seconds)	N/A	N/A
binlog event size	The size of a binlog event that the binlog replication unit reads from the relay log or the upstream MySQL	N/A	N/A
DML queue remain length	The length of the remaining DML job queue	N/A	N/A
total sqls jobs	The number of newly added jobs per unit of time	N/A	N/A
finished sqls jobs	The number of finished jobs per unit of time	N/A	N/A
statement execution latency	The duration that the binlog replication unit executes the statement to the downstream (in seconds)	N/A	N/A
add job duration	The duration tht the binlog replication unit adds a job to the queue (in seconds)	N/A	N/A
DML conflict detect duration	The duration that the binlog replication unit detects the conflict in DML (in seconds)	N/A	N/A
skipped event duration	The duration that the binlog replication unit skips a binlog event (in seconds)	N/A	N/A
unsynced tables	The number of tables that have not received the shard DDL statement in the current subtask	N/A	N/A
shard lock resolving	Whether the current subtask is waiting for the shard DDL lock to be resolved. A value greater than 0 indicates that it is waiting for the shard DDL lock to be resolved	N/A	N/A

Instance

In the Grafana dashboard, the default name of an instance is DM-instance.

Relay log

Metric name	Description	Alert	Severity level
storage capacity	The total storage capacity of the disk occupied by the relay log	N/A	N/A
storage remain	The remaining storage capacity within the disk occupied by the relay log	An alert occurs once the value is smaller than 10G	critical
process exits with error	The relay log encounters an error in DM-worker and exits	Immediate alerts	critical
relay log data corruption	The number of corrupted relay logs	Immediate alerts	emergency
fail to read binlog from master	The number of errors encountered when relay log reads the binlog from the upstream MySQL	Immediate alerts	critical
fail to write relay log	The number of errors encountered when the relay log writes the binlog to disks	Immediate alerts	critical
binlog file index	The largest index number of relay log files. For example, "value = 1" indicates "relay-log.000001"	N/A	N/A
binlog file gap between master and relay	The number of binlog files by which the `relay` processing unit is behind the upstream master	An alert occurs when the number of binlog files by which the `relay` processing unit is behind the upstream master exceeds one (>1) and the condition lasts over 10 minutes	critical
binlog pos	The write offset of the latest relay log file	N/A	N/A
read binlog duration	The duration that the relay log reads the binlog from the upstream MySQL (in seconds)	N/A	N/A
write relay log duration	The duration that the relay log writes the binlog into the disk each time (in seconds)	N/A	N/A
binlog size	The size of a single binlog event that the relay log writes into the disks	N/A	N/A

Task

Metric name	Description	Alert	Severity level
task state	The state of subtasks for migration	An alert occurs when the subtask has been paused for more than 10 minutes	critical
load progress	The percentage of the completed loading process of the load unit. The value range is 0%~100%	N/A	N/A
binlog file gap between master and syncer	The number of binlog files by which the binlog replication unit is behind the upstream master	N/A	N/A
shard lock resolving	Whether the current subtask is waiting for sharding DDL migration. A value greater than 0 means that the current subtask is waiting for sharding DDL migration	N/A	N/A